S2E4 - linux cli network tools cheat sheet

title: S2E4 - linux cli network tools cheat sheet

author: Nicholas Morrison nick@nanocat.net

draft: false

tags: [network, workshop, arista]

categories: [workshop]

noindex: true

`net-tools`

net-tools is an old suite of network-related tools
- netstat (for looking at open sockets, and the routing table)
- ifconfig (interface config, for managing wired network interfaces)
- iwconfig (same but for wireless interfaces)
- route (for managing the routing table)
- iptunnel (for creating tunnels)
- arp (for managing the ARP cache) (Address Resolution Protocol)

`iproute2`

iproute2 superceded net-tools, and includes more modern utilities
- ss (for looking at sockets)
- ip (for doing almost everything)
  - ip route (manage routing tables)
  - ip address (manage ip addresses)
  - ip neigh (manage ARP cache)
  - ip tunnel (manage tunnels)
- iw (managing wireless interfaces)

The `ip` tool

ip manages many many aspects of linux networking
ip route = manage your routing table (try ip -c route)
ip netns = manage network namespaces (try ip netns exec clab-www-pc1 ip -c route)
ip address = manage ip addresses (don’t forget -c for colour - ip -c address)
ip neigh = manage ARP cache. (Other hosts in the same layer 2 network are your neighbours.)
ip -c neigh = with colour!

The `ss` tool

ss gives us information about SOCKETS
a socket is a channel for communicating with a process
can be network sockets or unix sockets
(we only care about network sockets right now)
ss -t -l = listening TCP sockets
ss -t -a = listening and non-listening TCP sockets
ss -u -l = listening UDP sockets
ss -t | grep ssh = show active ssh connections